In recent years, from the viewpoint of reduction of the equipment maintenance costs and reduction of environmental load, weathering resistance improvement of the polymer material used under a severe condition such as outdoors is strongly required.
For the purpose of weathering resistance improvement of a polymer material used as a coating material, patent document 1 proposes adding a hindered amine light stabilizer having a piperidine skeleton whose a nitrogen atom is bonded to a various kinds of OR group (hereinafter, referred to as “NOR-HALS”), among hindered amine light stabilizers having a piperidine skeleton (hereinafter, referred to as “HALS”), to coating material components. Although the NOR-HALS has an advantageous effect of weathering resistance improvement of the polymer material, there is a problem that it slowly vanishes from the polymer material by migration or volatilization and the advantageous effect decreases with time.
For the purpose of solving this problem, patent document 2 proposes copolymerizing a polymerizable NOR-HALS (hereinafter, referred to as “polymerizable NOR-HALS”) having a vinyl group in a molecule to add it to coating material components.